Abstract: A bicycle frame part having a disproportionally enlarged end section and a method for making the same. The tube may be used as a bicycle frame part, and it may include a first section having a thickness, a second section configured to be forged from a first shape having a thickness that is different from the thickness of the first section to a second shape having a thickness that is less than the thickness of the first shape. The second shape of the second section may be proportionally enlarged relative to the first shape of the second section.

Abstract: A bicycle frame part having a disproportionally enlarged end section and a method for making the same. The method may include disproportionally enlarging an end section of an aluminum alloy tube of a bicycle frame part includes the steps of (a) drawing the tube to form a thin section and a thick end section, (b) radially and proportionally enlarging the cross-section of the thick end section of the tube by forging the tube in such a manner that the wall thickness of the thick end section after being enlarged is substantially the same as that of the thin section, and (c) disproportionally varying the cross-section of the thick end section of the tube by forging the tube obtained in step (b).

Abstract: A multi-stage tube forging method for disproportionally enlarging an end section of an aluminum alloy tube of a bicycle frame part includes the steps of (a) drawing the tube to form a thin section and a thick end section, (b) radially and proportionally enlarging the cross-section of the thick end section of the tube by forging the tube in such a manner that the wall thickness of the thick end section after being enlarged is substantially the same as that of the thin section, and (c) disproportionally varying the cross-section of the thick end section of the tube by forging the tube obtained in step (b).